(From Wikipedia) A domed city is a kind of fictional structure that encloses a large urban area under a single roof. In most descriptions, the dome is airtight and pressurized, creating a habitat that can be controlled for air temperature and quality. Domed cities have been a fixture of science fiction and futurology since the early 20th century.

(From Wikipedia) In science fiction, floating cities are settlements that strictly use buoyancy to remain in the atmosphere of a planet. However the term generally refers to any city that is flying, hovering, or otherwise suspended in the air via any means technological or even magical.

(From Wikipedia) In physical cosmology, astronomy and celestial mechanics, anti-gravity is the idea of creating a place or object that is free from the force of gravity. It does not refer to the lack of weight (but not the lack of gravity) experienced in free fall or orbit, nor to balancing the force of gravity with some other force, such as electromagnetism. Instead, anti-gravity requires that the fundamental causes of the force of gravity be made either not present or not applicable to the place or object through some kind of technological intervention. Anti-gravity is a recurring concept in science fiction, particularly in the context of spacecraft propulsion. The concept was first introduced formally as “Cavorite” in H. G. Wells’ The First Men in the Moon, and has been a favorite item of imaginary technology since that day.

(From Wikipedia) The orgasmatron is a fictional electromechanical device that appears in the 1973 movie Sleeper, which also shows the effects of a related device, an orgasmic orb. Similar devices have appeared in other fictional works. The term has also been applied to a non-fictional device capable of triggering an orgasm-like sensation using electrodes implanted at the lower spine.

A transporter is a fictional teleportation machine used in the Star Trek universe. Transporters convert a person or object into an energy pattern (a process called dematerialization), then “beam” it to a target, where it is reconverted into matter (rematerialization). The term transporter accident is a catch-all term for when a person or object does not rematerialize correctly.

(From Wikipedia) A Hoverboard (or hover board) is a fictional hovering board used for personal transportation in the films Back to the Future Part II and Back to the Future Part III. Hoverboards resemble a skateboard without wheels or trucks. Through special effects the filmmakers depicted the boards hovering above the ground. During the 1990s there were rumors that hoverboards were not fictional and were in fact real. These rumors have been conclusively debunked. Some companies hoping to leverage the commercial success of the movies have marketed hovercraft vehicles as hoverboards, but these products have not been shown to replicate the experience depicted in the movies. Subsequent to the movies the hoverboard concept has been reused by many authors in various forms of media in fictional universes not directly related to Back to the Future.

Rayguns are a type of directed-energy weapon. They are a classic and widespread feature of science fiction. Types of raygun have various names: ray gun, death ray, beam gun, blaster, laser gun, phaser, etc. They supply the general role of guns in the scenarios of many stories. When fired, a raygun fires a ray, usually visible, usually lethal if it hits a human target, often destructive if it hits mechanical objects, with properties and other effects unspecified or widely varying.